The other day I covered the most common question we get about driving an electric car; it only makes sense that this post takes on the frequent follow-up’s statement.
Electric vehicles might work in the south but batteries don’t work up here in the cold.
Having been born and raised in Edmonton, Alberta I certainly know the challenges relating to our climate. After all, how many times do cars up here need a boost in winter because their battery couldn’t handle the cold? Are there any special considerations we are going to have to be aware of when we take delivery of our electric car? Well the simple answer is: of course… but it’s not going to be overly onerous.
The first obvious issue that we should face is how cold weather and winter is going to affect our ideal range (discussed here). Yes, the operational temperature of a battery is crucial to squeezing its maximum performance. Interestingly the exact same problem exists in Internal Combustion Engines (ICE). Overcoming cold temperature for an ICE is easy. Simply running the engine generates a tremendous amount of wasted heat (more than 60% of the energy used in running a gas ICE is turned into wasted heat. This means for every 10 L of gas burned in the average car, only 4 L is spent moving the car and 6 L is simply generating waste heat). In fact, it comes to the point where a system must be in place to prevent the opposite issue of overheating. That is why they are equipped with a cooling system where a liquid coolant is sent through passages in the engine block and heads. As this liquid travels through the system it absorbs the heat from the engine and is sent back to a radiator so that it can dump the collected heat before it’s sent for another pass. Some of this wasted heat can be diverted into the cabin to warm it up. That’s why, it might take some time for your cars heater to start putting out warm air. However, it’s important to remember that the cooling system must always be running to handle all the wasted heat from an ICE.
In an electric vehicle, the challenges change a little bit. The electric motor only loses around 10% of its energy to heat when it uses the battery to propel the motor. This means for the battery to effectively be warmed to an ideal temperature it must also include a system the ICE doesn’t have (a battery heater). So, on cold days the car will be forced to kick in this battery heater which will require more energy and this will directly impact our range. (Conversely, the battery does also have a radiator system in place to prevent the battery from overheating on excessively warm days.) Also, since there isn’t a large amount of wasted heat that can be used to heat the cabin, the cars also utilize an electric heater to keep everyone warm. These are very efficient and start working immediately, which dramatically decreases the amount of time they need to run.
So how do we translate that into our real-world use? I’ve reached out to the local Alberta Tesla community for their information and they let me know what sort of impact these systems have had. The major factor to the decrease in range occurs from the use of the battery heater. On days colder than -20C we can expect to see the range drop by as much as 20% (311 km down to 249 km). Luckily, there is a way to avoid this large loss. If you have the car plugged into a charger while the heater is running, then this initial heating can be done without using the battery. That means your car and cabin are at temperature when you start your trip and can expect to see a 5-15% (311 km down to 264 – 295 km) loss just to keep things warm as you drive.
One of the ways Albertan’s with ICE’s tackle the cold is by utilizing a remote starter so that the engine and cabin are warm before they head out to the vehicle. The Tesla takes this a step further. First of all, the cars all come with a mobile app that allows you to access many convenience features. So, you can activate the vehicles heaters from your phone at any time. Additionally, the cars are equipped with two other great features. First they can sync up with your calendar. This way, the car knows when you’re going to be leaving for the next appointment and it will automatically start to warm the car without you having to use the app. Second, you can have the car start to learn your behavior. If you have any part of your routine that regularly repeats, the car will start to adapt and automatically enable the climate controls you prefer. Of course, you could decide to not wait for your ICE or Electric to warm up before you start your trip, but until they get warm they would both have sever impacts to your economy/range.
Finally, I need to discuss the other big challenge: vehicle storage. There might be a time where the car won’t be parked in the comfort of a garage, what happens then? Well first, let’s look at what Tesla advises in their Model S manual:
For better long-term performance, avoid exposing Model S to ambient temperatures above 140° F (60° C) or below -22° F (-30° C) for more than 24 hours at a time.
That means, on a cold night you can leave your vehicle parked in a safe location without doing long term damage to the battery. If you needed a longer-term solution, it is advised to not leave your car out in the cold for longer than 24 hours. Luckily, if you needed to do this most of Alberta already has the needed infrastructure in place: plugs for block heaters. In a pinch you could leave your car parked in a safe lot, plugged into trustworthy power and the car will manage the battery temperature itself so that no long term damage occurs.
What do you think? What challenges do you think we haven’t addressed yet? Leave a comment below.